London, March 15 (IANS): One Direction star Louis Tomlinson's sister Felicite Tomlinson is dead. She was 18.

Felicite, an aspiring fashion designer, died on Wednesday at her studio apartment here after she collapsed following a suspected heart attack, reported thesun.co.uk.

The exact cause of the death was said to be "unexplained".

A source close to Louis said that the "Miss you" hitmaker is "devastated" by the untimely demise of his sister.

"Felicite was an absolutely adored young woman who was loved by Louis and her whole family. They are all totally devastated, as you can imagine. She had so many friends and was such a positive happy person. It's a massive loss to the world.

"She was a loveable, caring, bright, passionate, popular and beautiful young lady," added the source.

It is also reported that Louis has pulled out of a performance on Comic Relief. He had been due to perform his new single live on one of the charity shows.